Insects play a big role in our ecosystems. They provide decomposition and nutrient cycling services, pollinate crops, and are a food source for birds and other animals. In monetary terms, researchers have valued the services insects offer various ecosystems at $57 billion per year in the US alone.
One of the largest contributing factors to the peril of many insects is human-caused light pollution, but something as easy as changing a light’s hue may significantly reduce the attraction for multitudes of insect species, ultimately preventing insect harm and death.
Conservation biologist Jessica Deichmann recently published a study in Insect Conservation and Diversity that found that LED bulbs shone through an amber-colored filter greatly reduced the number of insects drawn to its glow. Deichmann and her team also noted that disease-carrying insects were especially attracted to white LED light, so avoiding this kind of light around workspaces and homes could help protect our health.
Prior studies have discovered that insects favor white light over amber light, which is why to prevent insect harm (and to avoid having bugs obstructing our screens) many of us will find a night-mode setting on our devices that will switch the backlight from harsh blue light to a softer orange. This light is known as “artificial light at night,” or ALAN. However, Deichmann’s paper is the first to demonstrate the impact of different light hues in environments that have never been illuminated.
Deichmann and her team conducted this study to recommend lighting that would cause the least ecological harm. Overall, amber lights or ALAN are less harmful and attract significantly fewer insects, save for two groups of bioluminescent insects who preferred the amber-colored lights.
This is because ALAN can be confusing to insects that rely on light signals to mate. ALAN has also been found to make insects lethargic or inactive, disturbing the reproduction process. More studies must be conducted to find out which insects are attracted to which light wavelengths, but Deichmann’s study is enough to provide some easy and practical suggestions for commercial operators and homeowners.
She suggests installing amber-colored bulbs, which are available at most hardware stores, for outdoor lighting. She also says to ensure your porch light is focused on where you need it, rather than shining up into the sky. Motion detector switches for outdoor lights, closing curtains, and turning off unnecessary indoor lights are also bug-friendly adjustments.